Nix: use CMake for builds instead of Meson

Build using submodules instead of patching the build process and using
Nix derivations of the subprojects.

From this commit on, you'll have to change the Hyprland flake url to
`git+https://github.com/hyprwm/Hyprland?submodules=1`

flake.lock

@@ -29,9 +29,11 @@
     "hyprland-protocols": {
       "inputs": {
         "nixpkgs": [
+          "xdph",
           "nixpkgs"
         ],
         "systems": [
+          "xdph",
           "systems"
         ]
       },
@@ -114,12 +116,10 @@
     "root": {
       "inputs": {
         "hyprcursor": "hyprcursor",
-        "hyprland-protocols": "hyprland-protocols",
         "hyprlang": "hyprlang",
         "hyprwayland-scanner": "hyprwayland-scanner",
         "nixpkgs": "nixpkgs",
         "systems": "systems",
-        "wlroots": "wlroots",
         "xdph": "xdph"
       }
     },
@@ -138,28 +138,9 @@
         "type": "github"
       }
     },
-    "wlroots": {
-      "flake": false,
-      "locked": {
-        "lastModified": 1713731601,
-        "narHash": "sha256-bdcKdtLkusvv85DNuJsajZLFeq7bXp+x5AGP1Sd4wD8=",
-        "owner": "hyprwm",
-        "repo": "wlroots-hyprland",
-        "rev": "5c1d51c5a2793480f5b6c4341ad0797052aec2ea",
-        "type": "github"
-      },
-      "original": {
-        "owner": "hyprwm",
-        "repo": "wlroots-hyprland",
-        "rev": "5c1d51c5a2793480f5b6c4341ad0797052aec2ea",
-        "type": "github"
-      }
-    },
     "xdph": {
       "inputs": {
-        "hyprland-protocols": [
-          "hyprland-protocols"
-        ],
+        "hyprland-protocols": "hyprland-protocols",
         "hyprlang": [
           "hyprlang"
         ],